*: revise comments

Signed-off-by: Fullstop000 <fullstop1005@gmail.com>

src/db/mod.rs

@@ -358,7 +358,7 @@ pub struct DBImpl {
     // all relative methods are using immutable borrowing,
     // we still need to mutate the field `mem` and `im_mem` in few situations.
     mem: ShardedLock<MemTable>,
-    im_mem: ShardedLock<Option<MemTable>>, // iff the memtable is compacted
+    im_mem: ShardedLock<Option<MemTable>>, // There is a compacted immutable table or not
     // Have we encountered a background error in paranoid mode
     bg_error: RwLock<Option<WickErr>>,
     // Whether the db is closing

src/record/reader.rs

@@ -56,7 +56,7 @@ pub struct Reader {
     // NOTICE: we probably mutate the underlying file in the FilePtr by calling `seek()` and this is not thread safe
     file: Box<dyn File>,
     reporter: Option<Box<dyn Reporter>>,
-    // iff check sum for the record
+    // We should check sum for the record or not
     checksum: bool,
     // Last Read() indicated EOF by returning < BLOCK_SIZE
     eof: bool,

src/record/writer.rs

@@ -52,7 +52,7 @@ impl Writer {
     pub fn add_record(&mut self, s: &Slice) -> Result<()> {
         let data = s.as_slice();
         let mut left = s.size();
-        let mut begin = true; // indicate iff the record is a First or Middle record
+        let mut begin = true; // indicate the record is a First or Middle record
         while {
             assert!(
                 BLOCK_SIZE >= self.block_offset,
@@ -79,8 +79,7 @@ impl Writer {
             );
             let space = BLOCK_SIZE - self.block_offset - HEADER_SIZE;
             let to_write = if left < space { left } else { space };
-            // indicates iff the data exhausts a record
-            let end = to_write == left;
+            let end = to_write == left; // indicates whether the data exhausts a record
             let t = {
                 if begin && end {
                     RecordType::Full

src/version/mod.rs

@@ -466,7 +466,7 @@ impl Version {
             // beginning of range is after all files, so no overlap
             return false;
         }
-        // check iff the upper bound is overlapping
+        // check whether the upper bound is overlapping
         !self.key_is_before_file(self.files[level][index].clone(), largest_ukey)
     }
 

src/version/version_set.rs

@@ -158,7 +158,7 @@ pub struct VersionSet {
     pub compaction_stats: Vec<CompactionStats>,
     // Set of table files to protect from deletion because they are part of ongoing compaction
     pub pending_outputs: HashSet<u64>,
-    // iff should schedule a manual compaction, temporarily just for test
+    // Represent a manual compaction, temporarily just for test
     pub manual_compaction: Option<ManualCompaction>,
     // WAL writer
     pub record_writer: Option<Writer>,